Help with finding FV plz!

Could someone please help me on this asap Thanks

QUS:

The money that you save over the three years will form the deposit on a home Assuming that over the three years you salary does not increase, that you are going to save 15% of your gross monthly income (rounded to the nearest ten dollars) at the start of each month, and that the money that you save earns 6% interest compounding monthly, show all working to determine the total amount you will save in this time Any assumption must be stated.

Show also how the calculator may be used to check your answer.

My salary is $60,000

My solution:

( 1 + .06/12 ) x {[1 + .06/12]^36}-1 / (.06/12) x 750

= $29649.59

Could anybody please check that i did it right?

and also i have to prove this on my graphics calculator. I used the compound interest and entered

n= 36
I% = 6
PV = 0
PMT = -750
FV =
P/Y= 12

And i click the FV button and got the amount $29502.07. I found out that the calculator did it by (future value factor x payment) and did not (x 1.005).

my calculator is Casio FX9850GB

Does anyone have any suggestion? Do u think the calculator is not doing it properly or something?

Your calculator is correct.. . You have an extra factor in your formula . . .

The money that you save over the three years will form the deposit on a home.
Assuming that over the three years you salary does not increase,
that you are going to save 15% of your gross monthly income at the start of each month,
and that you earn 6% interest compounded monthly,
determine the total amount you will save in this time.